Apparatus and method for neighbor assisted combining for multicast services

ABSTRACT

A method and apparatus for neighbor assisted combining for localized multicast services. User equipment is sent a signal indicating the relationship between cells with respect to serving cells transmitting a common multicast transmission. At least a portion of the common multicast transmission is transmitted on the same resource on each serving cell. A pilot signal is transmitted on each serving cell, the pilot signal related to the at least a portion of the common multicast transmission on each serving cell. An interfering signal and a related pilot are transmitted on at least one different cell from the serving cells.

BACKGROUND

1. Field

The present disclosure is directed to a method and apparatus forneighbor assisted combining for localized multicast services. Moreparticularly, the present disclosure is directed to establishing atleast one serving cell and at least one extended serving cell forbroadcast and multicast services.

2. Description of Related Art

Presently, to deliver a multicast/broadcast stream in the Radio Accessnetwork (RAN) efficiently, two possible methods can be used. One issimulcast and the other is localized multicast. In simulcast mode, aMultimedia Broadcast Multicast Service (MBMS) service area is identicalto the RAN system coverage area. All the cells broadcast the same datausing the same resource. In Orthogonal Frequency Division Multiplexing(OFDM) based Enhanced MBMS (EMBMS), this could minimize the inter-cellinterference if the allocated resource element (RE) is identical, whichcan maximize the Bits/Hz. For a service with very large number of usersand the service is widely distributed in the RAN, simulcast can be anefficient way to go. For example, simulcast can be useful fortransmission of weather reports, music, movies, etc.

Simulcast is not efficient if the service area is much smaller than thesystem coverage area. For example, if the service is mostly focused inselected multiple cells, such as for clip replay for football stadiums,sport centers, local weather reports, or the like, it is not good toturn on all the cells in the system to deliver the localized service tojust the selected cells. Most of the MBMS service may fall into thiscategory of localized MBMS. In other words, simulcast is not anefficient way to maximize the Bits/Hz/km². For the localized MBMSservice, counting can be applied to determine the user status of thecells, such as to determine which cells contain users who desire theservice. Then an efficient radio bearer will be established in theappropriate cells to deliver the stream.

Unfortunately, during a localized multicast session, neighboring cellsinterfere with the localized service area cells. For example, neighborcells may transmit on the same resource element as the serving cells,which will interfere with the common multicast transmission. Thus, thereis a need for a method and apparatus for neighbor assisted combining forlocalized multicast services.

SUMMARY

A method and apparatus for neighbor assisted combining for localizedmulticast services. Cells are determined in which user equipment residethat desire a common multicast service. At least one serving cell fortransmitting the common multicast service is selected based on thedetermination. At least one extended serving cell is selected from atleast one serving cell neighbor cell which does not have user equipmentthat desire the common multicast service, the extended serving cellinfluencing transmissions on the serving cell. The common multicastservice is transmitted on the selected at least one serving cell.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the present disclosure will be described withreference to the following figures, wherein like numerals designate likeelements, and wherein:

FIG. 1 is an exemplary block diagram of a system according to oneembodiment;

FIG. 2 is an exemplary block diagram of a wireless communication deviceaccording to one embodiment;

FIG. 3 is an exemplary block diagram of a controller according to oneembodiment;

FIG. 4 is an exemplary flowchart illustrating the operation of a networkcontroller according to one embodiment;

FIG. 5 is an exemplary flowchart illustrating the operation of awireless communication device according to one embodiment;

FIG. 6 is an exemplary illustration of a system according to anotherembodiment;

FIG. 7 is an exemplary flowchart illustrating the operation of a networkcontroller according to another embodiment; and

FIG. 8 is an exemplary flowchart illustrating the operation of awireless communication device according to another embodiment.

DETAILED DESCRIPTION

FIG. 1 is an exemplary block diagram of a system 100 according to oneembodiment. The system 100 can include a network controller 140, anetwork 110, and at least one terminal 120. The terminal 120 may be awireless communication device, such as a wireless telephone, a cellulartelephone, a personal digital assistant, a pager, a personal computer, aselective call receiver, or any other device that is capable of sendingand receiving communication signals on a network including wirelessnetwork. The network can include cells 112, 114, and 116. These cellscan include serving cells 112 and extended serving cells 114.

In an exemplary embodiment, the network controller 140 is connected tothe network 110. The controller 140 may be located at a base station, ata radio network controller, at a multicast transmission server, anywhereelse on the network 110, and/or may be distributed throughout variousresources on the network 110. The network 110 may include any type ofnetwork that is capable of sending and receiving signals, such aswireless signals. For example, the network 110 may include a wirelesstelecommunications network, a cellular telephone network, a satellitecommunications network, and other like communications systems.Furthermore, the network 110 may include more than one network and mayinclude a plurality of different types of networks. Thus, the network110 may include a plurality of data networks, a plurality oftelecommunications networks, a combination of data andtelecommunications networks and other like communication systems capableof sending and receiving communication signals.

In operation, the controller 140 can determine cells 112 in which userequipment, such as terminals 120, reside that desire a common multicastservice. The controller 140 can select at least one serving cell 112 fortransmitting the common multicast service where the selection can bebased on the determination. The controller 140 can select at least oneextended serving cell 114 from at least one serving cell neighbor cellwhich does not have user equipment that desires the common multicastservice, the extended serving cell 114 influencing transmissions on theserving cell 112. The controller 140 can transmit the common multicastservice on the selected at least one serving cell 112.

According to a related embodiment, the controller 140 can signal to userequipment, such as terminals 120, a signal indicating the relationshipbetween cells with respect to the serving cells 112 transmitting acommon multicast transmission. The controller can transmit at least aportion of the common multicast transmission on the same resource oneach serving cell 112. The controller 140 can transmit a pilot signal oneach serving cell 112, the pilot signal related to the at least aportion of the common multicast transmission on each serving cell 112.The controller 140 can transmit an interfering signal and a relatedpilot on at least one different cell 114 from the serving cells 112.

For example, in a Multimedia Broadcast Multicast Service (MBMS), whenone MBMS session begins, the controller 140 can perform counting todetermine the user status of all the cells under the controller 140. Ifone cell has enough users, such as terminals 120, the cell can be aserving cell 112 and a broadcast mode can be established for the servingcell 112. The threshold for enough users may be a single user. If thereare no users in a cell, such as in cells 114 and 116, the cell may notbroadcast the data. A user, such as a terminal 112, can read MainControl Channel (MCCH) messages to determine if and how to combine aneighbor cell's 114 stream with its serving cell's 112 stream in orderto obtain the diversity gain and/or the power gain.

To elaborate, in Enhanced MBMS (EMBMS), interference may only come fromother cells. This can be a major bottleneck for system capacity. If thecontroller 140 can control the neighboring cells with largest averageinterference to broadcast the same data using the same Resource Element(RE) or at least not use that RE for other data transmissions, theinterference level can be much reduced. This can significantly increasethe system capacity. Thus, when the session begins, counting can beperformed. Each cell can report its user status to the controller 140.These serving cells 112 form the service area. The controller 140 canthen choose appropriate cells aside from the serving cells 112 that arethe candidates for the strongest interference for the cells in theserving area. This cells form extended serving cells 114 in an extendedserving area. The controller 140 can then control the extended servingcells 114 in the extended serving area to either broadcast the same dataas the serving cells 112 in the serving area, in the case that cellpower is available in an extended serving cell 114, or block theresource element that is used by an extended serving cell 114 in thecase that cell power is unavailable at the extended serving cell 114. Ifthe service area changes, such as by a user roaming, by a late joininguser, or the like, during the session transmission, the controller 140can adjust the extended serving area accordingly.

FIG. 2 is an exemplary block diagram of a wireless communication device200, such as the terminal 120, according to one embodiment. The wirelesscommunication device 200 can include a housing 210, a controller 220coupled to the housing 210, audio input and output circuitry 230 coupledto the housing 210, a display 240 coupled to the housing 210, atransceiver 250 coupled to the housing 210, a user interface 260 coupledto the housing 210, a memory 270 coupled to the housing 210, and atleast one antenna 280 coupled to the housing 210 and the transceiver250. At least one other antenna 282 may be coupled to the transceiver250 to create an antenna array. The wireless communication device 200can also include a multicast registration module 290, a receivercharacteristic adjustment module 292, and a multicast transmissiondecoder 294. The multicast registration module 290, the receivercharacteristic adjustment module 292, and the multicast transmissiondecoder 294 can be coupled to the controller 220, can reside within thecontroller 220, can reside within the memory 270, can be autonomousmodules, can be software, can be hardware, or can be in any other formatuseful for a module on a wireless communication device 200.

The display 240 can be a liquid crystal display (LCD), a light emittingdiode (LED) display, a plasma display, or any other means for displayinginformation. The transceiver 250 may include a transmitter and/or areceiver. The audio input and output circuitry 230 can include amicrophone, a speaker, a transducer, or any other audio input and outputcircuitry. The user interface 260 can include a keypad, buttons, a touchpad, a joystick, an additional display, or any other device useful forproviding an interface between a user and an electronic device. Thememory 270 may include a random access memory, a read only memory, anoptical memory, a subscriber identity module memory, or any other memorythat can be coupled to a wireless communication device.

In operation, the controller 220 can control the operations of thewireless communication device 200. The multicast registration module 290can register for reception of a local multicast service on a servingcell. The transceiver 250 can receive information regarding at least oneextended serving cell, the extended serving cell not including awireless communication device desiring the local multicast service. Thereceiver characteristic adjustment module 292 can adjust at least onereceiver characteristic of the wireless communication device transceiver250 based on the information regarding the at least one extended servingcell. For example, the receiver characteristic adjustment module 294 canadjust at least one receiver characteristic based on the extendedserving cell blocking a resource element related to transmission of thelocal multicast service on the serving cell. The receiver characteristicadjustment module 292 can also adjust at least one receivercharacteristic by applying antenna adaptive algorithm weights forcombining multiple antenna signals from the antennas 280 and 282.

In operation according to a related embodiment, the receiver in thetransceiver 250 can receive information regarding serving cells that aretransmitting a common multicast transmission. The receiver can alsoreceive the common multicast transmission, at least a portion of whichis transmitted on the same resource on multiple serving cells. Thereceiver can additionally receive a common broadcast pilot signalrelated to the common multicast transmission, the common broadcast pilotsignal being common to multiple cells. The multicast transmissiondecoder 294 can decode the common multicast transmission. The receivercharacteristic adjustment module 292 can adapt characteristics of thereceiver in response to receiving the information regarding the servingcells. The antennas 280 and 282 can comprise an antenna array. Thereceiver characteristic adjustment module 292 can adapt the antennaarray in response to receiving the information regarding the servingcells. A user interface can present the common multicast transmission toa user of the wireless device 200. For example, the common multicasttransmission can be presented via the display 240, the audio input andoutput 230 and/or the user interface 260.

FIG. 3 is an exemplary block diagram of a controller 300, such as thenetwork controller 140, according to one embodiment. The controller 300can include a housing 310, a processor 320 coupled to the housing 310, anetwork connection 350 coupled to the processor 320, media contentstorage 360 coupled to the processor 320, and a memory 370 coupled tothe processor 320. The media content storage 360 may be autonomous ormay be located in the memory 370. The controller 300 can also include acounting module 390, a serving cell selection module 392, an extendedserving cell selection module 394, a serving cell signaling module 396,and a transmission characteristic adjustment module 398. The countingmodule 390, the serving cell selection module 392, the extended servingcell selection module 394, the serving cell signaling module 396, andthe transmission characteristic adjustment module 398 can reside withinthe controller 320, can reside within the memory 370, can be autonomousmodules, can be software, can be hardware, or can be in any other formatuseful for a module on a controller. Also, each element of thecontroller 300 may be located at the network controller 140 or may bedistributed throughout the network 110. For example, the media content360 may be located at a media content provider, other elements may belocated at different network controllers, and other elements may belocated at different base stations on the network 110.

In operation, the processor 320 can control the operations of thecontroller 300. The counting module 390 can determine cells in whichuser equipment resides that desire a common multicast service. Theserving cell selection module 392 can select at least one serving cellfor transmitting the common multicast service, where the selection isbased on the determination. The extended serving cell selection module394 can select at least one extended serving cell from at least oneserving cell neighbor cell which does not have user equipment thatdesires the common multicast service, the extended serving cellinfluencing transmissions on the serving cell. The extended serving cellselection module 394 can also select the at least one extended servingcell based on the at least one extended serving cell having a largeaverage interference with the serving cell. The network connection 350can send the common multicast service for transmission on the selectedat least one serving cell.

The transmission characteristic adjustment module 398 can adjusttransmission characteristics on the extended serving cell to influencethe transmission of the common multicast service on the selected atleast one serving cell. For example, the transmission characteristicadjustment module 398 can adjust the transmission characteristics totransmit the common multicast service on the extended serving cell toinfluence the transmission of the common multicast service on theselected at least one serving cell. As another example, the transmissioncharacteristic adjustment module 398 can also block transmission on aresource of the extended serving cell, the resource influencing thetransmission of the common multicast service on the selected at leastone serving cell. The processor 320 can indicate, via the networkconnection 350, to user equipment on the selected at least one servingcell there is an unused resource on at least one neighbor cell. Theprocessor 320 can also indicate, via the network connection 350, to theuser equipment on the selected at least one serving cell, the physicalresource used on the serving cell and indicate which extended servingcells block the same resource. The user equipment can then adjustreceiver characteristics and/or antenna characteristics more efficientlybased on the knowledge of transmission characteristics of the neighborcells. The processor 320 can detect a change in a service area includingserving cell and the extended serving cell selection module 394 canadjust an extended service area including the extended serving cellbased on the processor 320 detecting the change.

In operation according to a related embodiment, the serving cellsignaling module 396 can signal to user equipment a signal indicatingthe relationship between cells with respect to serving cellstransmitting a common multicast transmission. The network connection 350can send a signal for transmitting at least a portion of the commonmulticast transmission on the same resource on each serving cell. Thenetwork connection 350 send a signal for transmitting a pilot signal oneach serving cell, the pilot signal related to the at least a portion ofthe common multicast transmission on each serving cell. The networkconnection 350 can send a signal for transmitting an interfering signaland a related pilot on at least one different cell from the servingcells. The pilot transmitted on each serving cell can be a phasereference for the common multicast transmission, and can be the samesignal transmitted on multiple serving cells. The signal indicating therelationship between cells can indicate which cells are serving cellstransmitting a common multicast transmission. The signal indicating therelationship between cells can also indicate the identity of a cell,such as an extended serving cell, that is transmitting on the sameresource as the serving cells. The signal indicating the relationshipbetween cells can additionally indicate the identity of a cell, such asan extended serving cell, that does not transmit on the same resource asthe serving cells.

FIG. 4 is an exemplary flowchart 400 illustrating the operation of thenetwork controller 140 according to another embodiment. In step 410, theflowchart begins. In step 420, the controller 140 can determine cells inwhich user equipment, such as terminals 120, reside that desire a commonmulticast service. In step 430, the controller 140 can select at leastone serving cell 112 for transmitting the common multicast service,where the selection is based on the determination. In step 440, thenetwork controller 140 can select at least one extended serving cell 114from at least one serving cell 112 neighbor cell which does not haveuser equipment that desires the common multicast service, the extendedserving cell influencing transmissions on the serving cell. Selecting atleast one extended serving cell can include selecting the at least oneextended serving cell 114 based on the at least one extended servingcell 114 having a large average interference with the serving cell 112.

In step 450, the controller 140 can adjust transmission characteristicson the extended serving cell 114 to influence the transmission of thecommon multicast service on the selected at least one serving cell 112.The controller 140 can adjust the transmission characteristics totransmit the common multicast service on the extended serving cell 114to influence the transmission of the common multicast service on theselected at least one serving cell 112. The controller 140 can alsoadjust transmission characteristics to block transmission on a resourceof the extended serving cell 114, the resource influencing thetransmission of the common multicast service on the selected at leastone serving cell 112. In step 460, the controller 140 can indicate tothe user equipment 120 on the selected at least one serving cell 112there is an unused resource on at least one neighbor cell. Thecontroller 140 can also indicate, to the user equipment 120 on theselected at least one serving cell 112, the physical resource used onthe serving cell and indicate which extended serving cells 114 block thesame resource. The controller 140 can also signal the power of atransmitted physical channel on an extended serving cell 114 to the userequipment 120 on the selected at least one serving cell 112. In step470, the controller 140 can transmit the common multicast service on theselected at least one serving cell 112. While transmitting the commonmulticast service, the controller 140 can detect a change in a servicearea including the serving cell 112 and adjust an extended service areaincluding the extended serving cell 114 based on detecting the change.In step 480, the flowchart 400 ends.

FIG. 5 is an exemplary flowchart 500 illustrating the operation of awireless communication device 200 according to another embodiment. Instep 510, the flowchart begins. In step 520, the wireless communicationdevice 200 can register for reception of a local multicast service on aserving cell 112. In step 530, the wireless communication device 200 canreceive information regarding at least one extended serving cell 114,the extended serving cell 114 not including a wireless communicationdevice desiring the local multicast service. In step 540, the wirelesscommunication device 200 can adjust at least one receiver characteristicof the wireless communication device 200 based on the informationregarding the at least one extended serving cell 114. Adjusting caninclude adjusting receiver characteristics based on the extended servingcell 114 blocking a resource element related to transmission of thelocal multicast service on the serving cell 112. Adjusting canadditionally include applying antenna adaptive algorithm weights forcombining multiple antenna signals. In step 550, the wirelesscommunication device 200 can receive the common multicast transmission,can receive a common pilot signal from one base station, and can receivea broadcast pilot signal from multiple base stations. In step 560, thewireless communication device 200 can combine a transmission from the atleast one extended serving cell 114 with a transmission from the servingcell 112. In step 570, the flowchart 500 can end.

FIG. 6 is an exemplary illustration of a system 600, such as the system100, according to another embodiment. The system 600 can include aterminal 610, such as a terminal 120, and base stations 620, 630, 640,and 650. The base stations 620, 630, and 640 may be located in servingcells 112. The base station 650 may be located in another cell 116 or anextended serving cell 114. The terminal 120 may be a wirelesscommunication device 200 and can include an antenna array 615.

In operation, multicasting radio systems can transmit the same signalfrom different cells or sites, such as base stations 620, 630, and 640in order to improve coverage. If a pilot is used for channel estimationpurposes, the pilot portion of the transmitted signal can be normallytransmitted in a similar or the same way as the data traffic so that thechannel affecting data may be estimated from the pilot. For example, thepilot and data can be transmitted on similar antenna patterns, onsimilar frequencies, at close times, etc. This similarly transmittedpilot or “common broadcast pilot” may then be used to determine thechannel that the data portion of the transmitted signal passes through,and so may be used in a receiver to decode the data.

The terminal 610 may adapt its receiver to maximize the received signalto noise ratio (SNR) of a desired signal, or it may maximize thereceived signal to interference and noise ratio (SINR). Since theperformance of a cellular radio telecommunication system is typicallylimited by interference, maximizing SINR generally gives betterperformance than maximizing SNR. A multiple antenna terminal 610 can beparticularly effective at maximizing SINR, as it can adapt its antennapatterns such that the pattern magnitude is large in the direction ofthe desired transmission, and small in the direction of an interferingtransmission. According to one embodiment, the present disclosuresupport these maximum SINR receivers.

A maximum SNR receiver, such as a maximum ratio combining receiver, isdescribed to contrast its operation with maximum SINR receivers. Anillustrative case is where the channel impulse response from a basestation antenna 620 to a terminal 610 may be modeled as a single complexcoefficient, which can be known as “flat Rayleigh fading.” This flatfading model can be appropriate for narrow band transmissions, such asthose often found in Frequency Division Multiple Access (FDMA) orOrthogonal Frequency Division Multiplexing (OFDM) systems, as well as incertain radio propagation environments. In these systems andenvironments, multicasting base stations 620, 630, etc. may transmit thesame signal at approximately the same times to the terminal 610, so thatwhen they are sufficiently synchronized the transmissions can combinesuch that they appear to be a single transmission traveling through achannel that is the sum of the individual channels. The signal receivedfrom N of these multicasting transmitters at a terminal 610 with Mantennas when both noise and interfering signals are present may beexpressed as:

$r = {{{\left( {\sum\limits_{i = 1}^{N}h_{i}} \right)x} + n + \left( {\sum\limits_{j = 1}^{L}{g_{j}y_{j}}} \right)} \equiv {{h_{d}x} + {Gy} + n}}$

Where:

-   -   r is an (M×1) column vector of the received signals and noise at        each of the M terminal antennas from the N antennas transmitting        the common desired signal    -   h_(i) is an (M×1) column vector of the channel impulse response        between the ith (of N) antennas transmitting a desired signal        and each of the terminal's antennas    -   g_(j) is an (M×1) column vector of the channel impulse response        between the jth (of L) antennas transmitting an interfering        signal and each of the terminal's antennas. Each g_(j) may be        estimated from a pilot transmitted in the same way as the        interfering signal, y_(j).    -   h_(d) is an (M×1) column vector of the composite channel impulse        response affecting the transmitted signal and it may be        estimated from the common broadcast pilot.    -   G is an (M×L) matrix, each column containing a g_(j)    -   n is an (M×1) column vector of the noise at each of the M UE        antennas    -   x is the desired common transmitted signal from multiple base        station antennas    -   y_(j) is the jth interfering signal    -   y is an (L×1) column vector of the interfering signals

When a terminal's antenna array combiner with weights w is used tocombine the received signals, r, the combiner output may be expressed:z=w ^(H) r

When we use the common assumption that the noise power on the receivedantennas 615 is the same, the received SINR, γ, at the antenna arraycombiner output, z, may be expressed as:

$\gamma = \frac{w^{H}R_{dd}w}{{w^{H}\left( {R_{II} + {\sigma_{n}^{2}I}} \right)}w}$

Where:

-   -   σ_(n) ² is the noise power    -   x^(H) is complex conjugate transpose (the “Hermitian” transpose)        of x    -   R_(dd)≡h_(d)h_(d) ^(H); and R_(II)≡GG^(H)

A maximum ratio receiver matches the array combining weights to thecomposite channel, so in this case:w=h_(d)

Since the maximum ratio combining receiver only needs estimates of thecomposite channel impulse response, h_(d), in this case the terminal 610does not need to estimate the channel impulse responses of theinterference. However, maximum ratio combining receivers are onlyoptimal in the presence of uncorrelated noise; so when correlatedinterference is present (i.e., when off diagonal elements of R_(dd) arenot zero), other receivers such as a minimum mean squared error (MMSE)receiver can have better performance. The MMSE receiver uses arraycombining weights that take the form:w=(R _(II)+σ_(n) ² I)⁻¹ h _(d)

R_(II) may be calculated as above using estimates of g_(j), since eachg_(j) may be estimated from a pilot transmitted in the same way as theinterfering signal, y_(j). Terminals typically need to know theidentities (spreading sequences, scrambling codes, OFDM subcarriers, orthe like) of the pilots used by the interfering transmitters, so thatthe g_(j) may be estimated. This information may be signaled to theterminal 610, or may be known apriori by the terminal 610. When theinformation is signaled to the terminal 610, it is often desirable toprovide the signaling about multiple interfering cells on a servingcell. This avoids the complexity involved when the terminal 610 receivescontrol signaling from multiple cells. If the terminal 610 does not knowthe identities of the pilots used by the interfering transmitters, or ifthe pilots are not transmitted in the same way as the interfering signal(i.e., they are not “phase references” for the interfering signals), itcan be difficult for the terminal 610 to use the interfering pilots todetermine MMSE combining weights.

Terminals often typically have to know which cells are transmittinginterference to calculate R_(II). This information can be especiallyimportant when the network does not transmit interference on a cell neara terminal 610, since that nearby cell would otherwise likely be astrong interference source, and the terminal 610 would likely adapt itsantenna pattern to attenuate it (reducing its ability to attenuate otherinterferers or to receive the desired common transmission). The networkmay therefore signal which cells do not transmit on a given channel, andso will not interfere with a common transmitted signal. Also, asindicated above, the terminal 610 can either be signaled identities ofpilots that may be used as phase references for interfering signals, orthe network transmissions can be constrained such that the terminal 610knows the identities apriori.

It is also useful for the terminal 610 to know which cells are thosethat are transmitting a common transmitted signal, so that they will notbe considered as one of those providing interference (and therefore oneof the L transmitters contributing to the interference terms in R_(II)).This determination can be difficult when only common broadcast pilot isused, since the N common broadcast pilots from the N transmitterscombine “in the air” to form a single received signal which reduces theidentifiability of the individual transmitters. Therefore, the networkmay signal on a serving cell if a nearby cell is one of thosetransmitting a common transmitted signal.

This knowledge of desired and interfering transmitters and their relatedpilots can enable improved terminal SINR performance over the case whereonly a common broadcast pilot is used (and where interference can not becontrolled as effectively).

The system 600 further illustrates the use of desired and interferingtransmitter and pilot information for the case where a maximum SINRreceiver is used. The terminal's antenna pattern 615 can be adapted tobe large in the direction of the combined transmission, while it issmall in the direction of the interfering transmitter 650. The combinedtransmission can appear to the terminal 610 to be from a singletransmitter and is illustrated as coming from a single direction. Whilethis is not required in the most literal sense, since adaptive arraysare capable of using a single degree of freedom to adapt to a coherenttransmission such as the combined transmission contemplated in thepreferred embodiment, it is reasonable for the purposes of illustrationin the system 600.

FIG. 7 is an exemplary flowchart 700 illustrating the operation of thenetwork controller 140 according to another embodiment. In step 710, theflowchart begins. In step 720, the controller 140 can determine cells inwhich user equipment, such as terminals 120, reside that desire a commonmulticast service and select at least one serving cell 112 fortransmitting the common multicast service. In step 730, the controller140 can send a signal to user equipment indicating the relationshipbetween cells with respect to serving cells 112 transmitting a commonmulticast transmission. The signal can be a signal indicating whichcells are serving cells 112 transmitting a common multicast transmissionand/or a signal indicating the identity of another cell, such as anextended serving cell 114, which is transmitting on the same resource asthe serving cells. In step 740, the controller 140 can transmit at leasta portion of the common multicast transmission on the same resource oneach serving cell 112. The common multicast transmission can bedetermined from a single information stream, such as from a mediacontent server, for broadcast to multiple users at multiple locations.The common multicast transmission can be transmitted on the servingcells 112 using the same physical layer attributes on each serving cell112. The same physical layer attributes can be the same spreading, thesame channel coding, the same error correction coding, the same timefrequency resources, the same frequency hopping pattern, and the like.In step 750, the controller 140 can transmit a pilot signal on eachserving cell 112, the pilot signal related to the at least a portion ofthe common multicast transmission on each serving cell 112. The pilottransmitted on each serving cell 112 can be a phase reference for thecommon multicast transmission and can be the same signal transmitted onmultiple serving cells 112. In step 760, the controller 140 can transmitan interfering signal and a related pilot on at least one different cellfrom the serving cells, such as an extended serving cell 114. In step770, the controller 140 can signal to a transmitting base station anindicator indicating not to transmit on a resource on a non-servingcell, such as on an extended serving cell 114. In step 780, thecontroller 140 can signal to user equipment the identity of a cell, suchas an extended serving cell 114, which does not transmit on the sameresource as the serving cells. The same resource on each serving cell112 can be the same slot, the same frequency, the same period, the sameWalsh codes, and the like on each serving cell 112. In step 790, theflowchart 700 can end.

FIG. 8 is an exemplary flowchart 800 illustrating the operation of awireless communication device 200 according to another embodiment. Instep 810, the flowchart begins. In step 820, the wireless communicationdevice 200 can receive information regarding serving cells 112 that aretransmitting a common multicast transmission. In step 830, the wirelesscommunication device 200 can adapt a receiver characteristic in responseto receiving the information regarding the serving cells 112. Forexample, the wireless communication device 200 can adapt a receiver oran antenna array in response to receiving the information regarding theserving cells 112. As a further example, the wireless communicationdevice 200 can attenuate an interfering signal by adapting its receiverto attenuate interference using the information regarding serving cells.In step 840, the wireless communication device 200 can receive thecommon multicast transmission, at least a portion of which istransmitted on the same resource on multiple serving cells 112. In step850, the wireless communication device 200 can receive a commonbroadcast pilot signal related to the common multicast transmission, thecommon broadcast pilot signal being common to multiple cells. In steps840 and 850, the wireless communication device 200 can also receive aninterfering signal and a related pilot from a different cell 114 fromthe serving cells 112. In step 860, the wireless communication device200 can adapt a receiver characteristic in response to receiving thebroadcast pilot. For example, the wireless communication device 200 canadapt a receiver or an antenna array in response to receiving thebroadcast pilot. As a further example, the wireless communication device200 can attenuate an interfering signal by adapting the receiver toattenuate interference using the information regarding serving cells andthe common broadcast pilot signal and the pilot related to theinterfering signal. In step 870, the wireless communication device 200can decode the common multicast transmission. In step 880, the wirelesscommunication device 200 can present the common multicast transmissionto a user of the wireless device via a user interface. In step 890, theflowchart 800 can end.

Thus, the present disclosure can provide neighbor assisted localizedmulticast. For example, when a session starts, counting can be performedby a network. Counting can be performed by having each cell report itsuser status, such as radio bearer status to a controller such as a RadioNetwork Controller. The cells that have users desiring a multicastsession can form a service area. The controller can choose appropriatecells except the cells in the serving area, which are the candidates forthe strongest interference for the cells in the serving area. Thesecells can form an extended serving area. The controller can control thecells in the extended serving area to either broadcast the same data asthe cells in the serving area, in the case that cell power is availableor block resource element that is used by the cell in the serving area,in the case that cell power is unavailable. The service area may changeby a user moving between cells, by a user joining a session after itstarts, or by any other similar event. If the service area changesduring the session transmission, the controller may adjust the extendedserving area as well.

The present disclosure can allow interference to be more finelycontrolled than existing simulcast or single frequency networks. Forexample, both the coverage area and interference sources can beexplicitly controlled. This can allow greater spectral efficiency perunit area and better coverage due to the precise control overinterference and a terminal's knowledge of desired and interferingsources. For example, a controller can signal information on whichneighbor cells have reserved and are not transmitting on a physicallayer resource, such as a channel, that a serving cell is transmittingon. This information can allow the terminal to configure an optimumreceiver in the terminal. The controller can also signal which neighborcells are transmitting on an identical physical layer resource, such asa channel, that a serving cell is transmitting on. For example anidentical physical layer resource can mean that the signals aretransmitted such that when the channel combines the signals from any twocells, the terminal cannot distinguish the transmissions from the twocells when the channels are within a scale factor of each other. Thiscan use identical scrambling, spreading, interleaving, or the like. Thecontroller can signal the information above on the serving cell.

The method of this disclosure is preferably implemented on a programmedprocessor. However, the controllers, flowcharts, and modules may also beimplemented on a general purpose or special purpose computer, aprogrammed microprocessor or microcontroller and peripheral integratedcircuit elements, an ASIC or other integrated circuit, a hardwareelectronic or logic circuit such as a discrete element circuit, aprogrammable logic device such as a PLD, PLA, FPGA or PAL, or the like.In general, any device on which resides a finite state machine capableof implementing the flowcharts shown in the Figures may be used toimplement the processor functions of this disclosure.

While this disclosure has been described with specific embodimentsthereof, it is evident that many alternatives, modifications, andvariations will be apparent to those skilled in the art. For example,various components of the embodiments may be interchanged, added, orsubstituted in the other embodiments. Also, all of the elements of eachfigure are not necessary for operation of the disclosed embodiments. Forexample, one of ordinary skill in the art of the disclosed embodimentswould be enabled to make and use the teachings of the disclosure bysimply employing the elements of the independent claims. Accordingly,the preferred embodiments of the disclosure as set forth herein areintended to be illustrative, not limiting. Various changes may be madewithout departing from the spirit and scope of the disclosure.

1. A method in a wireless network, the method comprising: signaling touser equipment a signal indicating the relationship between at least onecell with respect to at least one serving cell transmitting a commonmulticast transmission; transmitting at least a portion of the commonmulticast transmission on the same resource on the at least one servingcell; and transmitting a pilot signal on the at least one serving cell,the pilot signal related to the at least a portion of the commonmulticast transmission on the at least one serving cell; wherein a celldifferent from the at least one serving cell transmits an interferingsignal and a related pilot.
 2. The method according to claim 1, whereinthe signal is selected from the group of a signal indicating which cellsare serving cells transmitting a common multicast transmission and asignal indicating the identity of a cell that is transmitting on thesame resource as the serving cells.
 3. The method according to claim 2,wherein the pilot transmitted on the at least one serving cell is aphase reference for the common multicast transmission, and is the samesignal transmitted on multiple serving cells.
 4. The method according toclaim 2, wherein the common multicast transmission is transmitted on theserving cells using the same physical layer attributes on the at leastone serving cell.
 5. The method according to claim 4, wherein the samephysical layer attributes comprises at least one selected from the groupof the same spreading, the same channel coding, the same error detectioncoding, the same time frequency resources, and the same frequencyhopping pattern.
 6. The method according to claim 2, further comprisingsignaling to a transmitting base station an indicator indicating not totransmit on a resource on a non-serving cell.
 7. The method according toclaim 2, further comprising signaling to user equipment the identity ofa cell that does not transmit on the same resource as the serving cells.8. The method according to claim 2, wherein the same resource on the atleast one serving cell comprises at least resource one selected from thegroup of the same slot, the same frequency, the same period, and thesame spreading codes, on the at least one serving cell.
 9. The methodaccording to claim 2, wherein the common multicast transmission isdetermined from a single information stream for broadcast to multipleusers at multiple locations.
 10. A method in a wireless device, themethod comprising: receiving information regarding serving cells thatare transmitting a common multicast transmission; receiving the commonmulticast transmission, at least a portion of which is transmitted onthe same resource element on multiple serving cells; receiving a commonbroadcast pilot signal related to the common multicast transmission, thecommon broadcast pilot signal being common to multiple cells; decodingthe common multicast transmission; and receiving an interfering signaland a related pilot from a different cell from the serving cells. 11.The method according to claim 10, further comprising adapting a receiverin response to receiving the information regarding the serving cells.12. The method according to claim 10, further comprising presenting thecommon multicast transmission to a user of the wireless device via auser interface.
 13. The method according to claim 10, further comprisingattenuating the interfering signal by adapting the receiver to attenuateinterference using the information regarding serving cells and thecommon broadcast pilot signal and the pilot related to the interferingsignal.
 14. A network controller comprising: a processor configured tocontrol the operations of the network controller; a serving cellsignaling module coupled to the processor configured to signal to userequipment a signal indicating the relationship between cells withrespect to serving cells transmitting a common multicast transmission;and a network connection coupled to the processor the network connectionconfigured to send a signal for transmitting at least a portion of thecommon multicast transmission on the same resource element on eachserving cell, the network connection configured to send a signal fortransmitting a pilot signal on each serving cell, the pilot signalrelated to the at least a portion of the common multicast transmissionon each serving cell, the network connection configured to send a signalfor transmitting an interfering signal and a related pilot on at leastone different cell from the serving cells.
 15. The network controlleraccording to claim 14, wherein the pilot transmitted on at least oneserving cell is a phase reference for the common multicast transmission,and is the same signal transmitted on multiple serving cells.
 16. Thenetwork controller according to claim 14, wherein the signal indicatingthe relationship between cells indicates which cells are serving cellstransmitting a common multicast transmission.
 17. The network controlleraccording to claim 14, wherein the signal indicating the relationshipbetween cells indicates the identity of a cell that is transmitting onthe same resource as the serving cells.
 18. The network controlleraccording to claim 14, wherein the signal indicating the relationshipbetween cells indicates the identity of a cell that does not transmit onthe same resource as the serving cells.